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This invention relates to structural assemblies and components which are useful in the construction and maintenance of buildings or other structures. In particular, the invention is directed to a roof-mounted assembly which provides improved access to all portions of the exterior of such structures, with minimal interruption required to move the assembly or to include hoisting of materials. The assembly may additionally be formed from modular components which allow the assembly to provide varying span, strength, and rigidity characteristics which match the requirements of a particular application.
While building or maintaining various structures, and particularly tall buildings, it is often necessary to access the outside of the structure to either install building components (for example, façade materials) or to perform maintenance or refurbishing tasks on components already there. Historically, this required access was provided by the type of scaffolding which is based at ground level, and then is built upward to reach the height needed. Such scaffolding systems have typically been employed in close proximity to the building or structure being worked on, in order to provide artisans with a suitable area from which to perform their tasks. In the past, these scaffolding systems were constructed by bolting together vertical and horizontal members, and were usually not movable. They therefore allowed access to only one portion of the building or structure at a time. To move on to the next portion of the building, it was usually necessary to disassemble the scaffolding system, relocate its base, and then reassemble the members involved.
In addition to requiring a considerable amount of time and energy to dismantle and reassemble the scaffold each time it was moved, these prior art systems also presented significant safety risks to the workers using them. In addition, for most of these prior art scaffolding systems, the vertical height of the work platform could not be raised or lowered without dismantling a substantial portion of the scaffolding system. And, of course, for tall buildings, such scaffolding can quickly amount to an excessive amount of elements, and can be of questionable integrity and stability. Additionally, this traditional type of scaffolding doesn't provide enough strength to allow it to be used for lifting materials and components from the ground level to the height needed for the required installation or maintenance.
Another problem that has become prevalent in modern construction and maintenance activities is the need for scaffolding systems which are readily adaptable in size and shape, and which can be easily configured to accommodate a variety of accessories. As the pace of building construction has increased, and the time available for completing each task has correspondingly decreased, such scaffolding systems have become key elements in the construction process. The variety and complexity of building shapes and structures has increased dramatically in recent years. Designing and fabricating customized scaffolding systems to fit particular building shapes and to accommodate particular tasks can be both time consuming and relatively expensive. Contemporary scaffolding systems must therefore be adaptable for use in many configurations and applications. The assembled platforms must also have sufficient span strength and torsional rigidity to safely hold both the workers using the scaffolding and their materials.
Over time, several new approaches have been utilized to attempt to solve these problems. Cranes with very long booms have been used with limited utility and with limitations on the loads they can safely lift. Then, more creative minds (like that of the present inventor) discerned that more efficient, safer, and higher capacity lifting and access could be provided by suspending men and materials from the top of the structure downward, thereby utilizing higher strength tensile forces. Use of wire ropes and pulleys and horizontal beams facilitated moving men and materials up and down the outside of a structure.
Recently, several scaffolding system improvements have been disclosed which alleviate a number of the problems noted above. U.S. Pat. No. 4,234,055, issued to G. L. Beeche on Nov. 18, 1980, describes a mobile suspension scaffold which requires assembly and dismantling only once for each construction site, at the beginning and the end of the job, respectively. The system described may be moved along the sides of a building and around building corners without being disassembled. A suspended scaffold system which may be used either independently or in conjunction with this mobile scaffold is the folding scaffold described in U.S. Pat. No. 4,253,548, issued to G. L. Beeche on Mar. 3, 1981. The system disclosed therein includes a plurality of work platforms which are foldably linked together. U.S. Pat. No. 4,967,875, issued to G. L. Beeche on Nov. 6, 1990, describes a scaffolding system which employs modular components that may be combined to readily provide a variety of scaffold configurations and sizes. U.S. Pat. No. 5,203,428, issued to G. L. Beeche on Apr. 20, 1993, in turn discloses a scaffolding platform comprised of connected truss frames, which platform is particularly useful in conjunction with the scaffolding system disclosed by U.S. Pat. No. 4,967,875, and which may also be used independently thereof. The scaffold platform set forth in U.S. Pat. No. 5,203,428 is itself modular in nature, thereby further facilitating the assembly of scaffolding platforms which can conform to nearly any building size or shape. U.S. Pat. No. 5,214,899, issued to Beeche et al. on Jun. 1, 1993, describes a truss frame that is assembled from lightweight, modular components which are designed so as to provide the assembled frame with exceptional strength and rigidity. Finally, U.S. Pat. No. 8,347,580 issued to Beeche on Jan. 8, 2013, discloses a new structural member and modular beam system that provides improved strength, rigidity, and utility for building access assemblies.
What is needed, then, is a building access system which allows construction and maintenance workers to perform their tasks on all portions of the building's exterior, at any height between ground level and the top of the building, with minimal interruption to allow movement of the apparatus from one location to another. The desired system should, at the same time, be usable for lifting and placing the needed materials in the locations required for these workers to perform their tasks.
Accordingly, it is an object of the present invention to provide improved access to all portions of the exterior of a building or structure.
It is a further object to provide such access without needing to disassemble and reassemble, or to otherwise re-configure, the access assembly.
It is another object of the invention to provide a system which can also be used to lift, lower, and place in position objects other than workers, such as building components and materials.
It is an additional object of the present invention to provide an access system which can be assembled in a modular fashion, in order to accommodate varying requirements for size, strength, torsional rigidity, etc.
The building access system of the present invention comprises a turntable having an upper surface and a lower surface, a main tower attached to the turntable's upper surface, a boom tower pivotally attached to the turntable and disposed so as to form an angle with the main tower, and a balancing tower also pivotally attached to the turntable and also disposed so as to form an angle with the main tower. It further comprises means for changing these angles between the main tower and, respectively, the boom tower and the balancing tower, and a cathead pivotally attached to the end of the boom tower which is opposite the end attached to the turntable. The inventive apparatus may further comprise pressure sensing devices located and disposed so as to measure the pressure at each mounting point where the main tower is attached to the turntable, along with one or more leveling rods disposed so that, as the boom tower is raised upwardly and the angle between the main tower and the boom tower decreases in value by an associated amount, the angle between the cathead and the boom tower decreases in value by the same amount. The turntable may further comprise at least one support arm configured so that the bending forces experienced by the turntable are transferred to a larger diameter support structure. The invention also includes an elongated beam member which is especially useful for forming box beams, which member has a pair of symmetrical planar side elements which are perpendicular to each other and which are also connected together by a diagonal element. The inventive apparatus may be assembled using components which are small enough to fit in a building's elevator or stairway in order to move them from the ground level to the top of the structure, and light enough to be carried by manpower alone.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention itself, however, both as to its organization and its method of practice, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:
As is schematically illustrated by
Located between main tower 40 and turntable 20, at each mounting point where main tower 40 is connected to turntable 20, are pressure sensing devices 45 which individually measure the pressure at each such connection. Alternatively, these pressure sensing devices may be located in the turntable assembly. In operation, boom tower 60 is raised or lowered into its desired position for the required work access. Balancing tower 80 has attached thereto sufficient counterweights 81, that balancing tower 80 can be raised or lowered to a position where it counterbalances boom tower 60. It does so by changing the effective length of the moment arm created by counterweights 81. This position is found by monitoring pressure sensing devices 45, and stopping when the pressures measured by said devices are all approximately the same. At that position, the forces on main tower 40 are essentially all in a downward direction, with very little bending force or torsional force on main tower 40. This type of operation and relationship between main tower 40, boom tower 60, and balancing tower 80 is schematically illustrated in
Main tower 40, boom tower 60, and balancing tower 80 may be constructed from any suitable conventional materials. As illustrated in
Utilizing the above described modular system also provides the capability of assembling the inventive apparatus without requiring any lifting equipment, using manpower alone, while simultaneously complying with safety guidelines mandated by the Occupational Safety and Health Administration (OSHA) or state and local governments. As schematically illustrated in
In a typical arrangement, as shown in
In applications where additional resistance to bending and torsional forces is required, a “post tensioning” technique may be employed with the tower assembly. A wire or cable may be anchored at one longitudinal end of the tower by attaching it to one of the corners of the “box,” and then strung in a diagonal direction to the opposite corner of the adjacent “box” formed by the connected assembly of members, and then strung in the opposite diagonal direction to the opposite corner of the next adjacent “box” formed by the connected assembly of members. This “crisscrossing” type of stringing is continued along the length of the tower, to the opposite longitudinal end. Preferably, at least one more of such wires or cables is similarly anchored at the corner of the end box which is oppositely located to the first cable's anchor point, and then strung similarly in opposite diagonal directions with respect to the first cable, continuing until reaching the opposite longitudinal end of the tower. Once the wires or cables are strung, a pulling force of a predetermined amount is applied to each one before it is anchored to the associated longitudinal end of the tower, so as to create a residual tension in the respective wire or cable. This residual tension serves to resist bending or torsional forces applied to the tower by external loads attached to the tower. Optimally, four such tensioning wires or cables are used, so that this resistance is provided in both directions perpendicular to the tower and both rotational directions. Also, in order to shorten the lengths along the wire or cable which are unanchored, and therefore most likely to be the locations where undesirable stretching of the cable or wire would occur, at each location where the wire or cable crisscrosses another wire or cable, clamps can be added. These clamps will act as anchoring points for both of the clamped wires or cables, and will thereby minimize stretching or slippage of either cable.
At least one fixed length leveling rod 61 is disposed between boom tower 60 and cathead 100, with one end of leveling rod 61 attached to cathead assembly 100 and other end thereof attached to turntable 20. As boom tower 60 is raised upwardly and the corresponding angle between main tower 40 and boom tower 60 decreases in value by an associated amount, the length of leveling rod 61 remains at its fixed distance. As a result, the tab connecting cathead 100 to leveling rod 61 rotates about its pivot point, thereby causing cathead assembly 100 to similarly pivot. The angle between boom tower 60 and the horizontal axis of cathead 100 thereby increases in value by the same amount as the decrease in the angle between main tower 40 and boom tower 60. By this mechanism, the horizontal plane of the cathead always remains level, regardless of upward or downward movement of boom tower 60. Two such leveling rods 61 may be employed, disposed in a spaced apart relationship, in order to provide additional resistance to twisting forces on the cathead.
As illustrated by
Slewing ring 23 includes gear teeth which cooperate with a driving gear attached to a driving mechanism, such as an electric motor. In the embodiment shown, slewing ring 23 is attached to the outer surface of the turret assembly and is configured as a pinion type gear 24 driven by one or more motors 25 also disposed around the outside of the turret assembly. Alternatively, slewing ring 23 may be attached to the inner surface of the turret assembly and driven by one or more motors disposed inside the turret assembly. Turret 22 further includes means for mounting the turret assembly to a supporting structure, and means for allowing rotational movement of turret 22 with respect to said supporting structure. Typically, such a configuration includes two circularly shaped plates joined together by a pivot pin, with bearings disposed between the plates so as to facilitate rotational movement between these plates. One of said plates is attached to said support structure and remains stationary with respect thereto, while the other plate rotates around said pivot pin. The plate which rotates has disposed on its upper surface means for attaching main tower 40. Boom tower 60 and balancing tower 80 may each also be pivotally attached to this same means, or they may alternatively be pivotally attached to main tower 40.
Located around the outer circumference of turntable 20, and disposed in a spaced apart relationship thereto, is circularly shaped track 26. As illustrated in
At least one support arm 29 extends radially outwardly from turret 22, configured so that the inner end thereof is attached to turret 22 and the outer end thereof is attached to at least one caster wheel 30 which rolls on said upper surface of track 26. In the embodiment shown in
By this mechanism, the moment arm of resistance to said bending forces is significantly increased, thereby allowing a relatively small diameter turret to sustain force levels that would heretofore require a much larger turret diameter. This improvement is significant in applications where the turret must be located on the roof of a building. As described above, for those applications, the turret and associated components must be small enough to fit in stairways or elevators, and they must be light enough for workers to be able to lift them and maneuver them to the roof top. In the embodiment illustrated, the circular track is comprised of modular sections which can be separately transported to the roof top and then assembled there. All of the associated components may also be formed as modular elements which are small enough and light enough to facilitate transport to the roof area for assembly at that location. The turret itself may even be formed with handles which allow workers to hold onto it.
In some applications, it might be desirable for the assembly of this invention to be moveable on the roof top itself. In that case, the inventive apparatus includes means for providing such movement, connected to the support structure for turntable 20. In one embodiment, this means comprises one of the types of trolley systems where one or more trolleys are connected to said support structure and one or more trolley rails are connected to the building.
Referring now to
Attached to support structure 101 is turntable 102 which is similar in construction and function to turntable 20. Turntable 102 comprises a similar arrangement of a turret which includes a slewing ring affixed thereto. This slewing ring includes gear teeth which cooperate with a driving gear attached to a driving mechanism, such as an electric motor. The slewing ring may be attached to the outer surface of the turret assembly and may be configured as a pinion type gear driven by one or more motors also disposed around the outside of the turret assembly. Alternatively, the slewing ring may be attached to the inner surface of the turret assembly and driven by one or more motors disposed inside the turret assembly. Similar to turret 22, the cathead turret also further includes means for mounting the turret assembly to cathead supporting structure 101, and means for allowing rotational movement of the cathead turret with respect to said cathead supporting structure 101. Typically, such a configuration includes two circularly shaped plates joined together by a pivot pin, with bearings disposed between the plates so as to facilitate rotational movement between these plates. One of said plates is attached to said cathead support structure and remains stationary with respect thereto, while the other plate rotates around said pivot pin. If needed to meet the strength requirements of a particular application, turntable 101 may also include a circularly shaped track, support arms, and caster wheels, all arranged in a similar configuration to that described above in conjunction with turntable 20.
The plate which rotates has disposed on its upper surface means for attaching cathead cross beam 103, with the plane containing the horizontal axis of cathead cross beam 103 being generally parallel to the plane containing said upper surface. In the cathead's “neutral” position, the longitudinal axis of cathead cross beam 103 is generally disposed at a perpendicular angle to the longitudinal axis of boom tower 60. Upon activation of the driving mechanism for turntable 102, cathead cross beam 103 rotates leftward or rightward and the angle between the longitudinal axis thereof and the longitudinal axis of boom tower 60 changes correspondingly. In this manner, the longitudinal axis of cathead cross beam 103 may be aligned with the outer edge surface of the structure for which access is being provided.
Mounted on cathead cross beam 103 is means for lifting and lowering at least one load item. In the embodiment illustrated in
As an added safety feature, a “blocstop” type of cable monitor may be disposed between hoist motor 104 and sheave 107, as illustrated by blocstop 108. Blocstop 108 is configured so that it monitors the speed with which cable 105 passes therethrough, and if that speed exceeds a predetermined threshold, blocstop 108 acts as a brake which stops the cable from further movement. By this mechanism, cable movement at the speed expected while hoist motor 104 is winding or unwinding is allowed, but cable movement at a faster speed is stopped. Hence, if hoist motor 104 fails and the load item starts to fall, blocstop 108 will be activated, cable 105 will be stopped from further movement, and the load item will be prevented from falling to the ground.
For even greater safety, the means for attaching cable 105 to said load item includes at least one load sheave 109 which is attached to said load, and at least one blocstop 110 which monitors the speed with which cable passes therethrough, in the same manner as described above for blocstop 108. Preferably, two such sheaves 109 and blocstops 110 are employed at each attachment to the load item, in the configuration shown in
The load item being lifted or lowered may be either an object which needs to be moved or a basket from which workmen can access the structure being worked on. When the load item is a workmen basket, it is preferable that two sets of load sheaves 109 and blocstops 110 are employed, located at horizontally opposite ends of basket 112 in a spaced apart relationship from each other, in the manner illustrated by
The above-described arrangement is particularly beneficial for applications where workmen safety regulations issued by the Occupational Safety and Health Administration (OSHA) or state and local governments are in effect. Those regulations typically require that a worker who is at risk for falling off the structure must be tethered to that structure. However, those regulations allow the workmen to be tethered to the basket they are in (rather than the structure itself) while being raised or lowered, if that basket is configured as illustrated in the figures. Essentially, the basket shown is attached to the cathead cross beam by two lifting devices (rather than a single lifting device). Furthermore, the basket is attached by the equivalent of four separate cables. In the manner illustrated, these safeguards provided by the inventive apparatus meet or exceed the applicable OSHA requirements.
Basket 112 may be comprised of any suitable materials, in any suitable configuration. In a particularly useful embodiment, basket 112 is assembled from the structural members and modular beam system shown in U.S. Pat. No. 8,347,580 issued to Gregory L. Beeche. Using these components, the basket itself can even be formed as one or more modular units, and then fastened together as a basket assembly. The single unit shown in
Basket 112 may further comprise means for receiving, maneuvering, and/or installing building components, such as glass façade sections. One such means is illustrated in
Additionally, the inventive apparatus can accommodate those occasions where it is not necessary to raise or lower basket 112, but is instead desirable to raise or lower one or more other load items using one or more of hoists 104. In that situation, basket 112 may be raised all the way up to cathead cross beam 103 and attached thereto so that is suspended therefrom. Any suitable means may be employed for this task.
As illustrated in
In the alternative embodiments illustrated in
It is known that a cylindrically-shaped tube provides equal strength in the vertical and horizontal directions, and has excellent resistance to twisting forces. As such, it typically does not require any bracing to meet strength requirements; instead, the thickness of the tube wall and/or the diameter of the tube can be increased to the point where the desired strengths are achieved. However, most scaffolding applications do not require equal amounts of horizontal and vertical strength, and a cylindrical design is therefore inefficient in that the member includes more metal material in certain locations than is necessary. Furthermore, the cylindrical shape of the member requires the use of special, non-standard accessories for attaching other items to the tube.
A square-shaped or rectangularly-shaped tube provides a much better shape for attaching accessory components, while retaining much of the resistance to vertical load and twisting forces which is characteristic of a cylindrically shaped tube. However, a square-shaped or rectangularly-shaped tube presents its own difficulties with respect to attaching the members to like members and to other components, including difficulty in accessing the interior of such tubes in order to fasten such components.
The inventive structural member illustrated in
At least one planar diagonal element 302 connects side elements 301 to each other at locations on each which are spaced apart from the edge locations where side elements 301 are joined at a 90 degree angle. The two-dimensional cross-section of diagonal element 302 is shaped as shown in the drawing, and the depth of the plane extends along the length of the beam element (in the third dimension, into the paper). In the embodiment illustrated in
Arranging side elements 301 and diagonal element 302 in the symmetrical fashion illustrated in
In the embodiment shown in
Alternatively, beam elements 300 may be fastened to each other by other suitable means. As illustrated in
For some applications, it might be desirable to add accessory structures to the box beam assembly, for such purposes as adding strength or rigidity to a particular corner thereof or facilitating attachment of other components to the box beam. For example, L-shaped element 306 may be disposed so that the vertex of its 90 degree angle is located adjacent to and abuts the vertex of the 90 degree angle formed by side elements 301, and so that each of its legs is located adjacent to and abuts the interior of the corresponding portion of the respective side element 301. Again, this element may also be distributed along the length of the box beam either as discrete pieces or as a continuous piece. Similarly, rectangularly-shaped tube 308 may be disposed so that the exterior surface of one of its corners is located adjacent to and abuts the interior surface of the corner formed where side elements 301 form their 90 degree angle, and so that the two planar outer surfaces of tube 308 which form said corner are located adjacent to and abut the interior of the corresponding portions of the respective side elements 301. Also similarly, tube 308 may be distributed along the length of the box beam either as discrete pieces or as a continuous piece. For either of these embodiments, attachment of the respective additional element to the abutting portions of side element 301 (by any suitable means) serves as “bracing” for the associated corner of beam element 300, resulting in increased rigidity of that corner and correspondingly increased resistance to twisting forces. Depending upon the strength needed or the particular components which are to be added to the exterior of the box beam, more than one of the foregoing items may be utilized at the same time. This flexibility in configuration allows the inventive box beam to satisfy the requirements of a wide variety of applications. Moreover, when that application is finished, the added items may be removed, so that the box beam represents the basic building block once again.
In addition to providing means for fastening together multiple beam elements 300 into a box beam assembly, and providing means for adding strength and/or rigidity to the assembled box beam, each of bar stock 304, U-shaped member 305, L-shaped element 306, rectangularly-shaped tube 307, and square-shaped tube 308 may be employed to facilitate attachment of other components to the box beam. At the particular location on the exterior of the box beam where it is desirable to attach such a component, any one of these five items may added to the interior of the box beam, in the manner illustrated in
Many different types of additional components may be attached to the box beam in accordance with the foregoing description. They may be either “standard” commercially available items which have been used for other purposes, or “custom” ones specifically configured to have features which cooperate with the inventive box beam. An example of the latter type is illustrated in
For convenience and modularity, the fastening system described hereinabove may include a plurality of openings 312 formed in side elements 301, located and spaced apart as shown in
However, although modularity is enhanced by using the symmetrical arrangements just described, the exact locations and spacing of openings 312 can be varied, if necessary to meet the requirements of a particular application. In general, openings 312 are located so that fasteners may be inserted therethrough and also through correspondingly located openings in such items as bar stock 304, U-shaped member 305, L-shaped element 306, rectangularly-shaped tube 307, and square-shaped tube 308. As described hereinabove, each of these items may be utilized to either join together multiple beam elements 300 into a box beam assembly, provide means for adding strength and/or rigidity to the assembled box beam, or facilitate attachment of other components to the box beam.
In the particularly useful embodiment illustrated in
The openings through L-shaped element 306 shown in
Regardless of which joining item is used, whether it be bar stock 304, U-shaped member 305, L-shaped element 306, rectangularly-shaped tube 307, or square-shaped tube 308, it may be placed so that the end thereof is flush with the end of the associated beam element 300. In such a configuration, the joining item is only employed to join together multiple beam elements 300; for example, it may join together four beam elements 300 into a square-shaped box beam assembly, as described hereinabove. Alternatively, the joining item may be placed so that the end thereof extends beyond the end of the associated beam element 300, in a configuration where the joining item overlaps the end of an adjoining beam element 300 which is disposed in an end-to-end relationship with the first beam element 300. In this configuration, the joining item may serve to connect two or more beam elements 300 in an end-to-end assembly which increases the effective length of the overall beam member. Of course, the same joining item may be used to also join together multiple beam elements 300 into a full box beam assembly of the type shown in
For applications where the joining item also serves as the “nut” for the fastening bolt, as previously described,
For some applications, it might be desirable for the cross-section of the box beam to be rectangular rather than square. For such applications, bar stock 304 shown in
Finally,
It can be seen from the foregoing discussion that the building access system of the present invention provides the ability to move workers and materials to any location adjacent to the exterior of the structure involved, without needing to disassemble and reassemble, or to otherwise re-configure, the access assembly. The inventive system allows construction and maintenance workers to safely perform their tasks on all portions of the building's exterior, at any height between ground level and the top of the building, with minimal interruption required to move the assembly or to include hoisting of materials. The assembly may additionally be formed from modular components which can be specifically chosen and configured to have sufficient reach, span strength, and torsional rigidity which match the requirements of a particular application.
While the invention has been described in detail herein in accord with certain preferred embodiments thereof, many modifications and changes therein may be effected by those skilled in the art. Accordingly, it is intended by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.
This application is related to, and claims priority to and the benefit of, provisional application No. 63/101,274, filed on Apr. 22, 2020.
Number | Date | Country | |
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63101274 | Apr 2020 | US |